For the past few days, Gigi and I have been completely unable to send e-mail from our Mac laptops at home. Mail.app will try to send messages, but by and large they don't go anywhere. I have been having a certain amount of luck using Gmail's SMTP server, but it's a minor pain to try to send a message from one of my University accounts (which I use for the third year OS course I'm teaching this term), or from my.Mac account (my mail personal account), only to get an error dialog a minute or two later asking me to select a different server. Gigi hasn't been so fortunate -- she can't send anything at all.

Tonight I decided to look into this, and as it turns out, without announcement or fanfare two or three days ago my ISP decided to block all access to external port 25 requests. Thus, I had to try and find alternate ports for my.Mac and University servers..Mac supports SSL, so that wasn't too hard to find, but the University only lists port 25. After some experimentation trying some SSL and SSL alternate ports, I discovered by chance that they also accept SMTP connections on port 26 (which might be new to allow people around the local cable monopoly's port 25 blocking, in which case they ma not be advertising the new port yet).

In the end, everything is working again. The cable company claims it's being done to try to fight spam, but really it seems to me that if more providers do this, there will be organizations that instead of implementing SSL and authentication for SMTP simply do what the University has done and make the service available on port 26, simply shifting the problem to a different port. And even with SSL and authentication for SMTP, does anyone think its going to be difficult for botnet creators to simply query the necessary connection credentials from Windows users Outlook settings and just use them?